This might be a daft question, but is there a way of having a default player? e.g. Lets say i have Plex app open on both an iPad and also a Fire TV, however i would like to browse through the movies on the iPad and select play, which would automatically play on the Fire TV and not on the iPad without any further input. But if the Plex app is not open on the Fire TV then it would play on the iPad.
No. There is no such feature to set a default playback device. You need to manually specify where the playback will go.